Evidence overview, from most cited to more specific
Most of the landmark sauna–longevity studies were conducted in predominantly male Finnish cohorts, reflecting sauna culture and workforce-based recruitment at the time.
As a result, the strongest data for reduced cardiovascular and all-cause mortality apply mainly to men. Evidence in women is more limited due to underrepresentation, not known harm.
The physiologic mechanisms of heat exposure (vasodilation, cardiovascular load, endothelial adaptation) are not sex-specific, making benefits in women biologically plausible, but with lower certainty.
Foundational sauna–longevity evidence
Study design
Prospective population-based cohort
2,300 middle-aged men
Follow-up up to ~20 years
Traditional dry Finnish sauna (80–90 °C)
Key findings
Clear dose–response relationship
3–5 sauna sessions per week associated with:
Lower all-cause mortality
Lower cardiovascular mortality
Lower sudden cardiac death risk
Why it matters
This is the most cited and influential sauna study, forming the backbone of nearly all modern sauna–longevity claims.
Landmark study
Laukkanen et al., JAMA Internal Medicine, 2015
PMID: 25705824
Dose matters
Study design
Extended analyses of Finnish cohorts
Observational, long-term follow-up
Key findings
Compared with once-weekly sauna use, 3–5 sessions per week were associated with:
Lower fatal cardiovascular events
Lower coronary heart disease risk
Why it matters
The dose–response relationship strengthens biological plausibility and reduces the likelihood that findings are due to chance alone.
Study
Laukkanen et al., European Journal of Epidemiology, 2018
PMID: 30178212
Mechanistic cardiovascular evidence
Study types
Physiologic studies
Clinical trials of repeated thermal exposure
Key findings
Improved endothelial function
Reduced arterial stiffness
Blood pressure reductions after repeated sessions
Why it matters
Vascular aging and endothelial dysfunction are central drivers of cardiovascular disease and mortality.
Key references
Hannuksela & Ellahham, American Journal of Medicine, 2001
PMID: 11165553
Kihara et al., Journal of the American College of Cardiology, 2002
PMID: 11869837
Clinical trials in heart failure
Study design
Structured far-infrared sauna therapy
Typically ~60 °C, 15 minutes heat followed by rest
Small, controlled clinical trials
Key findings
Improved endothelial function
Improved cardiac performance
Reduced cardiac events in chronic heart failure patients
Why it matters
This is the strongest clinical evidence for infrared-based thermal therapy, though limited to specific patient populations and smaller samples.
Key studies
Kihara et al., JACC, 2002
PMID: 11869837
Miyata et al., Circulation Journal, 2008
PMID: 19304125
Putting the evidence together
Study type
Narrative and systematic reviews
Key conclusions
Long-term mortality associations are established for dry Finnish sauna
Infrared sauna evidence is supportive but limited
Benefits are driven by heat-induced cardiovascular and vascular adaptations, not light-specific effects
Key review
Kunutsor et al., Mayo Clinic Proceedings, 2018
PMID: 30077204
The strongest and most cited data support dry Finnish sauna
Evidence is primarily observational, not randomized mortality trials
Consistency, dose–response, and mechanistic data increase confidence
Evidence in women is supportive but less robust due to cohort limitations